Devices for controlling the firing of charges of powder or explosives from a distance



Sept. 4. 1956 M SCHLUMBERG 2,761,385 DEVICES FOR TROLL G THE FIRI OF CHARGES OF POWDER EXPL VES FROM A DISTANCE Filed Oct. 24, 1951 5 Sheets-Sheet 1 F I63. HT/yawn,

Ma /F651 Ja/wmalsxak EZMWMZMQ ATTORNEYS.

pt. 4. 1956 M. SCHLUMBERGER 2,761,385

DEVICES FOR CONTROLLING THE FIRING OF CHARGES OF POWDER OR EXPLOSIVES FROM A DISTANCE Filed Oct. 24, 1951 5 Sheets-Sheet 2 AT TO RNEYS pt. 4, 1956 M SCHLUMBERGER 2,761,385

DEVICES FOR. CONTROLLING THE FIRING OF CHARGES OF POWDER OR EXPLOSIVES FROM A DISTANCE Filed Oct. 24, 1951 5 Sheets-Sheet 3 'FIG.5.

#7412041 dc H4 u/mslszazz ATTORNEY S.

DEVICES FOR CONTRQLLING THE FIRING OF CHARGES F POWDER 10R EXPLOSIVES FROM A DISTANCE Marcel 'Schlumberger, Paris, France, assignor to Societe 'de Prospection Electriqne Procedes Schlun herger laris,

The present invention relates to devices which permit the selective firing from a distance of a plurality of charges of powder or explosive disposed at a remote'location asin a borehole drilled intojthe earth, for example. Morespecifically, ithas to dowith selectivefiring devices of the ,kind in which the firing of a primer causes the iipriming of a following charge by mechanical or other means, and it refers more particularly to devices of the type in which the firing is accomplishedelectrically.

gIn-certain .deyices such as sample takers forlu's'e in wells, ,tor example, a large number of sample taking tools ,are required to be ejected successively," and .it is desired to know at each moment precisely which ex'i- Plosive tool ,is firedso as .to insure that the shots will .be made at ,the exact well depth desired; Usually,.the' tools are connected to the. firing apparatus in the .well .by

flexible cables and they are adapted to be withdrawn from theformations by pulling onthecable on which the firing apparatus is suspended. In such apparatus, it is of primaryimportance not to take any risk of possible simultane'ousfiring of the charges corresponding. toseveral multiple-shot tools. If simultaneous firing were to take place, all ofthe multiple-shot tools would be driveninto the earth formations and any effort to withdraw them simultaneously by pulling on the supporting cable would involve the risk of applying excessive stresses to the latter.

,Theprincipal object of .the present invention is to provide new and improved selective firing "devices which definitely make it impossible for aplurality' of charges of powder orexplosiveto be fired simultaneously.

In firing devices of this ,typeavailable heretofore, a misfire resulting inthe failure of a charge to go ofi' usually made, it impossiblefor the subsequent charges to lie-fired because theyucouldnotbe primed. In the case of devices isedinsidea borehole, such an occurrence made'it necessary to pull up theentire' equipment for examination and r epairr", Anotherebject of the present invention is. to ohviate this drawback'at' least partially, 'andto permit firing of the following charges inspite ofthe .misfiring fpnech r -These and other objects of the invention may be obtained by connecting the different charges whose selective ignition is, tobe brought about tothree or'more separate electric circuits which areincapableof beingffed simulta i re,ously, .each circuit controlling one series of charges, the entire system being so arranged that onlyvone charge in eachmseries isprimed simultaneously, the firing of one charge in a series causing the priming of adefinite charge in. each of the other series, in the event that thisof these other definite charges have not already been primes preceding firings. According to another feature of the invention, the elec? tric primers of theunpr imed'c'harg'e's" aragr unaes ai their two ends so as to prevent "anypossibility destin d: leaks causing the premature firing of a charge. "liifadlditionfthe charges are preferably distributed 'in thfee' or mo'recircuifs so that, for instance, the c'a'se 'df th'ree iiaientecl Sept 1956 circuits, there are always two primed charge s belonging angs a turn 'causes or assures the priming of at least two other charges, and so forth.

it is also possible, according to the invention, to provide a device .for continuing shooting even if two successivecharges fail to go Oil. For this purpose, it is sufficient to arrange the system so that the discharge of each charge will cause the priming of three other 'charges, the h rs s e n r an ed i fea se ra e roups f d separately and successively by four electric circuits, the discharge -tone charge of a group assuring the priming of'itli're'e located, respectively, in the other three g oups in question. If it seems necessary, the possibility hree successive misfirings can beprovided-for by the priming of'four successive chargesdisposedin four other Fig. l is "aschematic diagram of athree-circuitqelect fir g d i caas ru ed ord n to the inv and intended, for instance, for firing chargesin a multipleshot device lowered in a borehole;

' ,Figs. 2 and 3 illustrate schematicallythe state of the havebeen fired;

,firing device of Fig. 1 after the first and second shots Fig. 4 is aview in side elevation of part shot device provided with a firing device according to theinventionj and Fig. 5 is a view in longitudinal section taken alongline 5 5 of Fig. 4. In the illustrative embodiment of the invention describedbelow, the firing device comprises priming mechanism mounted separately in three electric circuits, the discharge of each igniter in one ofthe circuits assuring the priming of the two following igniters arrangedQ-r spectively,in the other circuits. ln' Fig. 1, theigniters are shown diagrammatically by small-electric resistors R1-1, R21,- Rs1, R1-2,,R2-2, Ra-z, R1-3, Rz-s and R34 formed by filaments which cause the firingbyfthe fact that they are brought to incandescence by .the passage of the current. Although only nine resistors areshown in Fig. 1, obviously a greater or lesser number may be used and, in practice, the successive and'selective' firing of thirty charges or more may be readily provided for according to the invention. Resistors'R23 andR'ss are not shown in Figs. 2 and 3, since they are not immediately affected by the exemplary operation described hereinafter. As stated, the igniters are distributed in three groups which are adapted to be energized by three different electric circuits, the igniters of the first group being denoted by the designation R1, those of the second group by R2, and those of the third group. by R v The three groups of igniters are fed separately by means of three electric conductors, ll, 12, andi13, running from the apparatus in the borehole to the surface of the earth wherethey are connected to the fixed contacts. 14, 15 and to'each ofthe groups are adaptedtoibe connected between the corresponding conductor, on the one hand, and

of a multiplea ground formed by the body of the apparatus and designated by the reference character 21 in Figs. l-3, inclusive as will be described in greater detail hereinafter.

Two of the igniters, i. e. the two lower igniters Rl-l and R24, are connected, before the apparatus is lowered into the borehole, directly between the conductors 11 and 12 and the ground 21 so that they are primed before the start of the operations. On the other hand, the other igniters are not initially primed but their two ends are both connected to ground, as shown. Priming, which may, for instance, be effected in the manner described hereafter concerning more specifically the m-ulti-shot apparatus proper, or in any other manner, will consist in disconnecting one of the terminals of an unprimed igniter from ground and connecting it to the corresponding conductor 11, 12 or 13.

After the apparatus has been prepared, as outlined above, it will function in the following manner: the first charge is fired by supplying electric current to the conductor 11 thereby energizing the first primed igniter R1-1. The firing of the shot corresponding to the igniter R1-1, primes the igniter R3 1, so that the firing circuit is then in the condition shown in Fig. 2, i. e., the two igniters R2-1 and R3-1 alone being primed. Thereupon current is passed into the conductor 12 and the firing of the shot corresponding to the igniter RZ-l primes the igniter R1-z, so that the firing circuit is then in the state shown in Fig. 3. In this state, the igniter Rs-i can be ignited by causing a current to be passed into the conductor 13 and the firing of the shot corresponding thereto will prime the igniter Rz-z and so forth.

Hence, it will be seen that, in normal operation of the system described above, two igniters will always be primed but that, with a single source connected successively to each line, only one shot can be fired at a time.

In case an igniter misfires for one reason or another, it is still possible to continue firing. For example, if the igniter Rs 1 were to misfire, firing could be continued by passing current through the conductor to energize the igniter R1 -2 (Fig. 2). The firing of the shot corresponding to this igniter simultaneously primes the igniters Rz-z and R3 z as will be described in greater detail below. From this moment on, by causing the current to pass successively into the conductors 12 and 13 the firing of the shots corresponding to the igniters R24 and R3-: can be assured, which, in turn, will result in priming the igniters R1-3 and R24, and so forth; hence, a misfire by itgnedigniter will not prevent the following shots from being As stated above, Figs. 4 and 5, respectively, show part of a sample taking device for use in wells which is equipped with mechanism constructed according to the invention. The sample taker is similar to those used at the present time in that it consists of an elongated cylindrical body in which there have been provided transversely extending recesses forming gun barrels (there may be as many as thirty gun barrels formed along the body, or even more). In Figs. 4 and 5, only a portion of a sample taker having three guns is shown for purposes of illustration. Inside the gun barrels are disposed projectiles such as sample taking tools which may be formed by tubes which are adapted to be projected into the ground by the explosion of a charge of powder. Each of the sample taking tools is connected to the body of the apparatus by a flexible cable so that it can be pulled up with the body of the apparatus. Apparatus of this general character is shown in prior Patent No. 2,055,506 to Marcel Schlumberger.

In Figs. 4 and 5 the body of the apparatus 22 has formed therein a plurality of recesses 24-1, 24-2, 24-3 which form powder chambers. In front of these powder chambers are disposed a plurality of sample taking tools 29-1, 29-2, 29-3 which are connected to the body of the apparatus by the cables 30-1, 30-2, 30-3, respectively. The powder in the powder chambers 241, 24-2, 24-3, is adapted tobe ignited by a plurality of igniting means which are connected, respectively, to the three conductors 11, 12 and 13 (in Fig. 5 only the conductor 13 is seen). The igniting devices are preferably of the type disclosed in the copending application Serial No. 128,323, filed November 19, 1949, by Marcel Schlumberger, for Electrical Igniters, now Patent No. 2,681,701, issued June 22, 1954.

At the end of a metallic hollow tube 23-3, outwardly connected to the ground, is connected the filament Ra 1 which goes into the powder chamber 24-3. One end of the filament Rs-1 is connected to the tube 23-3 and, therefore, to the ground and its other end is connected by means of an insulated conductor 25-3 inside the tube 23-3 to a small blade 26-3 carried by an elastic element 27-3 which forms a spring. Normally, this blade 26-3 (Fig. 5) rests on a metal short-circuiting wire 28-3 which keeps it away from an insulated contact 31-3 carried by the conductor 13 and which, at the same time connects this blade to the ground. The wire 28-3, which is associated with the sample taker tool 29-3 which is adapted to be ejected by the combustion of the charge in the chamber 24-3 passes (Fig. 4) through the cable 30-2which connects the tool 29-2 to the apparatus and is attached to the cable 30-1 which connects the tool 29-1 to the apparatus.

In Fig.5, the igniter R3-1 is shown in the unprimed condition, while the igniter R2-1 is primed. In the primed position, the short-circuiting wire is missing, and the blade 26-2, because of the elasticity of the element 27-2, will make contact with the contact 31-2. In this position, the igniter R2 1 is connected between ground and the corresponding conductor 12. Assume now that the igniter R11 is also primed and that the corresponding sample taking tool is to be fired. The sample taking tool 29-1 is projected into the adjacent earth formation (not shown) and carries with it the cable 30-1 and the wire 28-3 attached to the latter. When the wire 28-3 is pulled out, the blade 26-3 will engage the contact 31-3 thereby priming the igniter R3-1.

If for some reason or another, the igniter R1-1 misfires and that, therefore, the sample taking tool 29-1 has remained in place, the firing can, nevertheless, be continued. Since the igniter Rz-1 is primed, by causing current to pass into this igniter from the conductor 12, the tool 29-2 can be ejected, and the cable 30-2, through which the wire 28-3 passes, will pull out the latter wire so that the igniter Ra-r will be primed. At the same time, since the cable 30-2 is also connected to the end of a wire 28-4 associated with the immediately following igniter R1-z (Fig. 1), ejection of the sample taker tool 29-2 will prime the following igniter R1-z so that, in all cases, after firing this shot, there will still be two primed igniters.

From the foregoing, it will be understood that the invention provides novel and highly effective firing mechanism for setting oif a plurality of explosive charges from a distance. By providing a single energizing conductor for each of a plurality of groups of charges and maintaining the majority of the igniters normally short circuited, possible simultaneous firing of all of the charges is avoided. Further, by causing the firing of any one charge to prime at least one charge in each of at least two. other groups of charges, it is possible to continue with the firing operations even if a misfire takes place.

Obviously, the specific embodiment described above may be modified within the scope of the invention. Thus, as stated above, provision can be made for the priming of more than two igniters so as to be able to continue firing operations even in the case of two consecutive misfires. The invention, therefore, is not to be limited save as defined in the following claims.

I claim:

1. In apparatus for firing a plurality of explosive charges from a distance, the combination of at least two electrical igniter means for said charges, means for short-circuiting one of said igniter means, a firing circuit including the other of said igniter means, and means responsive to ignition of said last-named igniter means for rendering said short-circuiting means inefiective.

2. In apparatus for firing a plurality of explosive charges from a distance, the combination of at least two electrical igniter means for said charges, means for short-circuiting at least one of said igniter means, a first firing circuit including a primed igniter means, a second firing circuit, means for rendering said short-circuiting means ineffective and for connecting the igniter means corresponding thereto in said second firing circuit thereby priming said corresponding igniter means, and means actuated upon ignition of said first firing circuit igniter means for operating said connecting means.

3. In apparatus for firing a plurality of explosive charges from a distance, the combination of at least two electrical igniter means for said charges, means for short-circuiting one of said igniter means, a first firing circuit including the other of said igniter means, a second firing circuit, means responsive to ignition of said lastnamed igniter means for rendering said short-circuiting means inefiective and for connecting said one of said igniter means in said second firing circuit, a source of electrical energy, and means for connecting said source selectively to said first and second firing circuits.

4. In apparatus for firing a plurality of explosive charges from a distance, the combination of a plurality of short-circuited electrical igniter means and at least two primed electrical igniter means for said charges, a first firing circuit including one of said primed igniter means, a second firing circuit including another of said primed electrical igniter means, a third firing circuit, a plurality of means for rendering the short-circuiting of said short-circuited electrical igniter means ineffective and for connecting them in said first, second and third firing circuits, and means actuated upon ignition of the igniter means in one of said first and second firing circuits for operating at least one of said rendering and connecting means.

5. In sample taking apparatus including a body adapted to be lowered into a well and having a plurality of laterally directed, longitudinally spaced apart gun barrels formed therein, a sample taking projectile in each of said gun barrels, and powder chamber means for each of said gun barrels each having electrical igniter means therefor, the combination of a plurality of means for short-circuiting all but at least two of said igniter means, a first firing circuit including one of said two igniter means, a second firing circuit including the other of said two igniter means, a third firing circuit, means actuated by ejection of the projectile corresponding to one of said two igniter means for rendering one of said short-circuiting means for a third igniter means ineffective and connecting said third igniter means in said third firing circuit, means connected to each projectile other than said projectile corresponding to said one of said two igniter means for rendering ineffective said shortcircuiting means for the igniter means in two adjacent powder chambers and for connecting them in two diflferent ones of said three firing circuits, respectively, a source of electrical energy at the surface, and switching means for connecting said source selectively to said first, second, and third firing circuits.

References Cited in the file of this patent UNITED STATES PATENTS 1,738,595 McBride Dec. 10, 1929 2,307,729 Foster Jan. 5, 1943 2,331,058 Stick Oct. 5, 1943 2,343,087 Schlumberger Feb. 29, 1944 2,511,408 Lebourg June 13, 1950 2,543,823 Barry Mar. 6, 1951 2,546,686 Bickel et a1 Mar. 27, 1951 2,569,511 Bickel et al. Oct. 2, 1951 

1. IN APPARATUS FOR FIRING A PLURALITY OF EXPLOSIVE CHARGES FROM A DISTANCE, THE COMBINATION OF AT LEAST TWO ELECTRICAL IGNITER MEANS FOR SAID CHARGES, MEANS FOR SHORT-CIRCUITING ONE OF SAID IGNITER MEANS, A FIRING CIRCUIT INCLUDING THE OTHER OF SAID IGNITER MEANS, AND MEANS RESPONSIVE TO IGNITION OF SAID LAST-NAMED IGNITER MEANS FOR RENDERING SAID SHORT- CIRCUITING MEANS INEFFECTIVE. 